When world-building there are certain key areas a writer should work on. Political structures, basic geography and the like are all obvious. One aspect which is less so, but quite easy and very useful for making a world more realistic, is the leisure activities of both the poor and the rich.
History gives us lots of great examples. Roman gladiatorial games are well-known (and unique, so far as I know, in human history), but there are plenty of others. The Aztecs played a ball game which involved the captain of the winning side (until a change centuries later when it was the captain of the losing side) getting his heart ripped out in sacrifice to some god or other. In the Middle Ages peasants played football, but it took place over an immense distance (miles and miles) with whole villages taking part and quite a lot of violence.
The Romans also enjoyed chariot racing, of course, which was very dangerous and outlived the gladiatorial games by centuries. In the Middle Ages hawking and hunting were very popular amongst the nobility.
Because we still play it bowling might seem a bit odd as an ancient game, but it has been around for centuries. Boxing too, although bare knuckle boxing is actually a lot safer than modern boxing. This is because boxing gloves cushion the knuckles, allowing people to hit one another in the face very hard. If you try this without a boxing glove you’ll break your hand before the other person’s face. So, death rates in bare knuckle boxing were much lower (a rare case of a sport becoming more dangerous over time).
Of course, in the past people often had greater (and more socially acceptable) bloodlust than today. Blood sports, from cockfighting (so popular in England practically every little village had a cockpit), badger-baiting and hare-coursing all the way up to bear-baiting, were very popular.
The Romans had a rather split personality when it came to animals. They often had a wide variety of pets (Emperor Tiberius hand fed his pet snake), but would gleefully watch them being slaughtered in the arena (in the Romans’ defence this was very equal opportunities of them, as they also cheered humans being thus killed). Pompey, before he ran off when Caesar approached, tried to bolster his popularity by hosting games, a common political ploy (the ancient equivalent of a pre-election Budget giveaway). However, the elephants he used were domesticated animals, who were terrified when attacked. The crowd were disgusted with Pompey for killing the tame animals, and it rather backfired as a political stunt.